I think that analogy is broken. Measuring a coastline more precisely doesn't just become more complex (measuring precisely often does), but actually increases the measured length towards infinity.
Unless you wanted to say that the same is true for software estimation, e.g. due to the measurements taking up more and more time.
Yes, I meant the time taken estimating. The act of measuring estimated hours becomes more complex because the closer you look, the more you see, you could do it forever and have to stop somewhere.
But maybe instead of infinity, it's better to say estimation can take longer than the work itself which has been the case a few times for me.
Unless you wanted to say that the same is true for software estimation, e.g. due to the measurements taking up more and more time.